The present invention relates to a scribing method and apparatus for forming or scribing a scribe line on a surface of a work (workpiece) of a brittle material such as plate glass, ceramics plate or the like.
In a known art, the Japanese Patent Laid-open Publication No. HEI 9-25134 discloses a scribing apparatus for forming a scribe line on a brittle material while applying a vibration thereto.
This known scribing apparatus has a structure in which an air-cylinder assembly includes an outer cylinder fixed to a support, an inner cylinder connected to one end of a vibration generating member, and a cutter holder connected to another end of the vibration generating member, the cutter holder being mounted on the support to be slidable. According to such structure, the air-cylinder assembly operates to urge the cutter holder so as to push the cutter held by the cutter holder against a work surface, and in such state, a high frequency voltage is applied to the vibration generating member to vibrate the cutter, thus forming the scribe lines on the work surface.
When the scribe line is scribed by using the scribing apparatus mentioned above, the scribing operation starts from an edge portion of the work surface, and in this operation, the edge portion of the work surface is locally destroyed by the vibration of the cutter. The scribe line is then scribed from this locally destroyed portion. That is, during the movement of the cutter along the work surface, the work surface is beaten or tapped at minute distances or intervals by the vibration of the cutter to thereby generate vertical cracks, which are grown from the locally destroyed portion as a base (or starting) portion of the scribe line.
In the conventional scribing method and apparatus mentioned above, for example, even in a case where it is desired to scribe a scribe line constituting a closed curved line, it is necessary to start the scribing operation from the edge portion of the work surface, which is essentially not necessary in such curved scribing line operation, and accordingly, the scribing operation takes much extra time.
In order to obviate such defect, it may be considered to start the scribing operation from a portion of the work surface apart from the edge portion. However, in such case, starting the growth of the vertical crack by the vibration of the cutter, so that a deep and good scribe line is formed is difficult. Furthermore, in a case of scribing a scribe line on a hard work, even if the cutter beats the work surface by the vibration, the cutter merely slides and moves on the work surface without scribing any scribe line, thus also causing a problem.
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide a scribing method and apparatus for scribing a scribe line in good condition in a short time.
This and other objects can be achieved according to the present invention by providing, in one aspect, a method of forming a scribe line on a surface of a work by using a scribing apparatus having a scribe body provided with an abutment member having a sharpened tip, and a vibration generating device for applying a vibration to the abutment member, wherein a base crack is formed on a scribing base point apart from an edge portion of the surface of the work, and the scribe line is formed with the base crack being an initial crack of the cracks forming the scribe line.
The base crack may be formed by applying an impact to the scribe body. More actually, the abutment member may be moved directly above the scribing base point by relatively moving the scribe body along the work surface in a state separated from the work surface. The scribe body may be lowered to allow the tip of the abutment member to abut against the scribing base point by a dead weight of the scribe body, and thereafter, the impact may be applied to the scribe body.
The scribing base point may substantially correspond with a scribing finishing point to thereby describe a closed curve line.
In another aspect of the present invention, there is provided a scribing apparatus for forming a scribe line on a surface of a work comprising a scribe body provided with an abutment member having a sharpened tip and a vibration generating device for applying a vibration to the abutment member, a support member for supporting the scribe body to be movable in a direction crossing the surface of the work, and an impact applying device for applying an impact to the scribe body.
The impact applying device may comprise an air-cylinder assembly supported by the support member, the air-cylinder assembly having a rod having an end portion to be brought into contact with the scribe body to thereby apply the impact to the abutment member.
The scribing apparatus may further comprise: a positioning device for moving one of the scribe body and the work in a direction along the surface of the work so as to locate the abutment member of the scribe body on a position at which the abutment member confronts a scribing base point formed at a portion apart from an edge portion of the work surface; a contacting/separating device for contacting or separating the sharpened tip of the abutment member to or from the work surface by moving one of the scribe body and the work in a direction crossing the work surface; a moving device for moving at least one of the scribe body and the work to relatively move the abutment member along a predetermined line to be scribed on the work surface; and a control device operatively connected to the contacting/separating device, the positioning device, the impact applying device, the moving device, and the vibration generating device to control the operations thereof to scribe the predetermined scribe line on the work surface, and the control device may control the contacting/separating device and the positioning device so as to oppose the abutment member to the scribing base point on the work surface while separating the abutment member from the work surface, control the contacting/separating device to abut the sharpened tip of the abutment member against the work surface, control the impact applying device so as to apply the impact to the scribe body, and control the moving device so as to scribe a predetermined scribe line on the work surface while controlling the vibration generating device to apply the vibration to the abutment member.
According to the present invention and structures mentioned above, since the scribing base point is set to a portion apart from the edge portion of the work to be scribed, it is not necessary to scribe an extra line, and hence, it is possible to scribe the scribe line, such as a closed curve line, in a short time, shortening the scribing work. Furthermore, the base crack is formed on the scribing base point by which the growth of the vertical crack can be promoted through the vibration to thereby scribe the scribe line.
The base crack can be easily formed by applying the impact by the air-cylinder assembly constituting the impact applying device. The scribing operations can be preferably controlled by the control device.